scholarly journals Field Optimization and Electrostatic Stress Reduction of Proposed Conductor Scheme for Pliable Gas-Insulated Transmission Lines

2019 ◽  
Vol 9 (15) ◽  
pp. 2988 ◽  
Author(s):  
Muhammad Junaid Alvi ◽  
Tahir Izhar ◽  
Asif Ali Qaiser ◽  
Hafiz Shafqat Kharal ◽  
Adnan Safdar
Keyword(s):  
Field Intensity ◽  
Electrostatic Field ◽  
Stress Reduction ◽  
Transmission Lines ◽  
Dielectric Breakdown ◽  
Experimental Investigations ◽  
Optimized Design ◽  
Potential Candidate ◽  
Semiconducting Film ◽  
Critical Consideration

The implementation of stranded conductors in flexible gas-insulated transmission lines (FGILs) requires field intensity minimization as well as field irregularity suppression in order to avoid dielectric breakdown. Moreover, the interdependence of enclosure and conductor sizes of FGILs regarding electrostatic aspects necessitate critical consideration of their dimensional specifications. In this research, geometric and electrostatic field optimization for FGILs regarding stranded conductors is performed. In addition, the effect of conductor irregularity on field dispersion is analyzed, and a semiconducting film (SCF)-coated stranded conductor is proposed as a potential candidate for FGILs. Considering the performed optimized design, an 11 kV scaled-down model of a 132-kV FGIL was also fabricated in order to practically analyze its electrostatic and dielectric performances regarding simple and SCF-coated stranded conductors. Simulation and experimental investigations revealed that the SCF-coated stranded conductor significantly minimized the field irregularity of the FGIL along with improving in its dielectric breakdown characteristics.

scholarly journals Optimized Design of Wind Turbine Blade Receptors Based on Electrostatic Field Theory

Electronics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1418
Author(s):  
Li ◽  
Lv ◽  
Li ◽  
Yue ◽  
Cao
Keyword(s):  
Field Theory ◽  
Electric Field ◽  
Wind Turbine ◽  
Field Intensity ◽  
Electrostatic Field ◽  
Electric Field Intensity ◽  
Optimization Design ◽  
Optimized Design ◽  
Lightning Stroke ◽  
Element Analysis

Lightning protection for blades is one of the most important factors for the safe operation of wind turbines. In view of the differences in the designs of blade receptors, a full-scale blade receptor model was constructed on the basis of the scaling experiment of the wind turbine and electrostatic field theory. By combining the electromagnetic finite element analysis with leader discharge theory, this study analyzed and discussed the influence of the protruding height of receptors and the design of receptor types on the lightning receiving effect of the blade, and the optimum design scheme of blade receptors was proposed. According to the results of this study, the field intensity distribution on the surface of the receptor was a high-boundary and low-middle structure. The receptor easily produced an upward connection leader as the lighting junction. The electric field intensity around the receptor was substantially distorted after 4 mm protrusion, which was approximately twice the electric field intensity of a flat right-angle receptor. The convex chamfer had multiple centralized lightning stroke points compared with the convex right-angle design, thereby exhibiting better solidification and reliability at the lightning stroke area, which are conducive to protecting the blade from lightning damage. The electric field intensity of the convex fillet was similar to the chamfer, but the radius of the electric field intensity of the convex fillet was small, and the attenuation of the electric field intensity with the radius was evident. This study provides a reference for further optimization design of blade receptors.

Improving electrospinning process by numerical analysis of 3-D computer models

2019 ◽  
Vol 38 (4) ◽  
pp. 1098-1110
Author(s):  
Anna Firych-Nowacka ◽  
Krzysztof Smolka ◽  
Sławomir Wiak
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Field Intensity ◽  
Electrostatic Field ◽  
Electric Field Intensity ◽  
Computer Models ◽  
Electrospinning Process ◽  
Strength Analysis ◽  
Original Solution ◽  
Content Type

Purpose Electrospinning is a method of the polymer super thin fibres formation by the electrostatic field. The distribution of electrostatic field affects the effectiveness of the electrospinning. Design/methodology/approach This paper presents various computer models that can improve the electrospinning process. The possibilities of modelling the electrostatic field in the design of electrospinning equipment are presented. Findings In the research part, the one focussed on finding a cylinder-shaped collector structure to limit the adverse effect of an uneven distribution of the electric field intensity on the collector. Originality/value The paper concerns the improvement of the electrospinning process with the use of electrostatic field modelling. In the first part, several possible applications of electrostatic models have been indicated, thanks to which the efficiency of the process has been improved. The original solution of the collector geometry was presented, which according to the authors, in comparison with previous models, gives the most promising results. In this solution, it was possible to obtain an even distribution of the electric field intensity while removing the unfavourable effect of the field strength increase on the outer edges of the collector. The most important aspect in this paper is electric field strength analysis.

scholarly journals Optimized Design of Modular Multilevel DC De-Icer for High Voltage Transmission Lines

Electronics ◽  
2018 ◽  
Vol 7 (9) ◽  
pp. 204 ◽  
Author(s):  
Jiazheng Lu ◽  
Qingjun Huang ◽  
Xinguo Mao ◽  
Yanjun Tan ◽  
Siguo Zhu ◽  
...  
Keyword(s):  
Transmission Lines ◽  
Engineering Application ◽  
Optimized Design ◽  
Multilevel Converter ◽  
Power Outage ◽  
Total Cost ◽  
Technical Performance ◽  
Promising Solution

Ice covering on overhead transmission lines would cause damage to transmission system and long-term power outage. Among various de-icing devices, a modular multilevel converter based direct-current (DC)de-icer (MMC-DDI) is recognized as a promising solution due to its excellent technical performance. Its principle feasibility has been well studied, but only a small amount of literature discusses its economy or hardware optimization. To fill this gap, this paper presents a quantitative analysis and calculation on the converter characteristics of MMC-DDI. It reveals that, for a given DC de-icing requirement, the converter rating varies greatly with its alternating-current (AC) -side voltage, and it sometimes far exceeds the melting power. To reduce converter rating and improve its economy, an optimized configuration is proposed in which a proper transformer should be configured on the input AC-side of converter under certain conditions. This configuration is verified in an MMC-DDI for a 500 kV transmission line as a case study. The result shows, in the case of outputting the same de-icing characteristics, the optimized converter is reduced from 151 MVA to 68 MVA, and the total cost of the MMC-DDI system is reduced by 48%. This conclusion is conducive to the design optimization of multilevel DC de-icer and then to its engineering application.

The Fundamentals of Electrostatic Spinning

1977 ◽  
Vol 47 (12) ◽  
pp. 780-789 ◽  
Author(s):  
Ismail Doĝu
Keyword(s):  
Field Strength ◽  
Electrostatic Field ◽  
Dielectric Breakdown ◽  
Mathematical Treatment ◽  
Lateral Vibration ◽  
Textile Fiber ◽  
Electrostatic Spinning ◽  
Spinning Process ◽  
Freely Suspended ◽  
Field Strengths

A mathematical analysis of uncrimping of textile fibers in an electrostatic field is given. One important result of this analysis is that a textile fiber is very little uncrimped in the field strengths that can possibly be used in this process, since higher field strengths cause a dielectric breakdown. A mathematical treatment of the orientation of fibers in an electrostatic field is also given. The amount of orientation depending on the fiber physical properties and process parameters are calculated. It is shown that a freely-suspended single fiber moving in an electrostatic field may perform either a periodic or nonperiodic lateral vibration depending on the magnitude of the electrostatic field strength. It is shown that in an electrostatic spinning process there is little fiber orientation in the time available before the fiber enters into the rotor-electrode. The critical value of the field strength determining whether a fiber will perform a periodic or nonperiodic movement is calculated. It is shown that the transfer of fibers of variable fineness by means of an electrostatic field from the feeding device to the twisting element is a randomizing process of the positions of fibers relative to each other, and this is rather important as far as the yarn evenness is concerned.

scholarly journals Optimized Design of Modular Multilevel DC De-Icer for High Voltage Transmission Lines

2018 ◽  
Author(s):  
Jiazheng Lu ◽  
Qingjun Huang ◽  
Xinguo Mao ◽  
Yanjun Tan ◽  
Siguo Zhu ◽  
...  
Keyword(s):  
High Voltage ◽  
Transmission Lines ◽  
Engineering Application ◽  
Optimized Design ◽  
Power Outage ◽  
Technical Performance ◽  
Promising Solution ◽  
High Voltage Transmission

Ice covering on overhead transmission lines would cause damage to transmission system and long-term power outage. Among various de-icing devices, modular multilevel converter (MMC) based DC de-icer (MMC-DDI) is recognized as a promising solution due to its excellent technical performance. Its principle feasibility has been well studied, but few literature discuss its economy or hardware optimization, thus the designed MMC-DDI for high voltage transmission lines is usually too large and too expensive for engineering applications. To fill this gap, this paper presents a quantitative analysis on the converter characteristics of MMC-DDI, and calculates the minimal converter rating and its influencing factors. It reals that, for a given de-icing requirement, the converter rating varies greatly with its AC-side voltage. Then an optimization configuration is proposed to reduce the converter rating and improve its economy. The proposed configuration is verified in a MMC-DDI for a 500kV transmission line as a case study. The result shows, in the case of outputting same de-icing characteristics, the optimized converter rating is reduced from 151 MVA to 68 MVA, and total cost of MMC-DDI is reduced by 48%. This analysis and conclusion are conductive to the optimized design of multilevel DC de-icer, then to its engineering application.

scholarly journals Currents in Line Conductors due to an Electron Avalanche

2021 ◽  
Author(s):  
Debasish Nath ◽  
Udaya Kumar
Keyword(s):  
Transmission Line ◽  
Transmission Lines ◽  
Basic Mechanism ◽  
Background Field ◽  
Modern World ◽  
Experimental Investigations ◽  
Electromagnetic Noise ◽  
Overhead Lines ◽  
Tem Mode ◽  
Induced Currents

<p>Transfer of bulk electric power required in the modern world can be realized only through EHV and UHV transmission lines. The scenario is dominated by overhead lines in which electromagnetic noise generated by corona is an important concern. Corona induced currents propagate along line conductors producing electromagnetic noise, which is essential to be quantified. In literature, large amount of work is based on experimental investigations which considers only limited frequency ranges and is not applicable to new line configurations. A set of semi-analytical methods have also been proposed, which employ the transmission line model for analysis. However, quasi-TEM mode of propagation inherently assumed by them has been questioned. Moreover, the corona current is modeled as shunt source without relating to the mechanism of induction due to corona. The present work aims to investigate the basic mechanism of current induction using an isolated avalanche developing under space charge modulated background field. The corresponding induced currents are quantified and the structure of the electric and magnetic fields is extracted. The basic issue with the long transmission line modelling is amply demonstrated. Even though single avalanche, being the basic process building corona is considered, general inferences can be drawn regarding corona on lines.</p>

Static, vibration, and buckling analyses and applications to one-sheet hyperboloidal shells of revolution

2002 ◽  
Vol 55 (3) ◽  
pp. 241-270 ◽  
Author(s):  
SN Krivoshapko
Keyword(s):  
Transmission Lines ◽  
Strain State ◽  
Power Transmission ◽  
Review Article ◽  
Experimental Investigations ◽  
Power Transmission Lines ◽  
Shells Of Revolution ◽  
Stress Strain ◽  
Arch Dams ◽  
Stress Strain State

The principal achievements of science and engineering in the sphere of design, construction, and static, vibrational, and buckling analysis of thin-walled constructions and buildings in the shape of hyperbolic surfaces of revolution are summarized in this review article. These shells are useful as hyperbolic cooling towers, TV towers, reinforced concrete water tanks, and arch dams. They are also used as supports for electric power transmission lines and as high chimneys. Several public and industrial buildings having the hyperbolic form are described in the review. The basic results of theoretical and experimental investigations of stress-strain state, buckling, and vibration are summarized. The influence of temperature and moisture on the stress-strain state of the shells in question is also analyzed. This review article contains 261 references.

Optimal Design and Experimental Investigations of Aluminium Extrusion Profiles for Lightweight of Car Bumper

2013 ◽  
Vol 585 ◽  
pp. 157-164 ◽  
Author(s):  
Jia Zhou ◽  
X.M. Wan ◽  
Y. Li ◽  
Q.J. Zhao
Keyword(s):  
Weight Reduction ◽  
Experimental Studies ◽  
Fem Simulation ◽  
Optimization Method ◽  
Bending Test ◽  
Crash Test ◽  
Experimental Investigations ◽  
Optimized Design ◽  
Extrusion Dies ◽  
Aluminium Extrusion

The present study aimed at developing an aluminium car bumper unit to replace the steel ones by using optimization based on experimental and FEM simulation results. The topology optimization method and response surface methodology (RSM) were applied in order to achieve an optimized design for the cross section of the crossbeam and the crash box, respectively. The three-points bending test and crash test for bumper unit were simulated to evaluate the optimization processes. The 6061 and 6063 aluminium alloy bumper unit has a weight reduction of 67% compared to the steel ones. The new extrusion dies were manufactured to produce profiles for the crossbeam and the crash box, respectively. Then the optimized extrusion profiles of crossbeam and crash box were verified by experimental studies. The performance tests were arranged to validate the experimental product. The mechanical properties of extruded aluminium crossbeam and crash box can satisfy the design requirements of products. The results indicate that the new designed unit can change the whole design of automotive parts for crash energy absorption, and definitely contribute to drastic weight reduction of steel parts.

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